There is a conventionally known display device which includes a fluorescent lamp on which letters and picture images are painted. The fluorescent lamp display device typically consists of a "normal" fluorescent lamp, used for illumination purposes; a fluorescent layer coated on the inner surface of a glass tube, in a fluorescent lamp, is made to radiate white light, as a result of electric discharge taking place inside the glass tube. The letters and picture images are painted on the outer surface of the glass tube, typically by using color ink which contains thermo-setting binders.
However, according to such a conventional display device, since the letters and picture images are painted on the outer surface of the glass tube with thermo-setting color ink, and since the letters and picture images do not emit light, they are only visible to the naked eye as dark areas against a background of white light, which is emitted from the surface of the glass tube. Therefore, the images or objects displayed are not as clearly visible to the viewer as is desired: the unattractive device consequently does not draw any attention. As a result, this device is neither an effective tool for advertisement nor ornamentation.